This is a practical selection of the commands we use most often. Press
<Tab> to see the listing of all available command (on your PATH).
On my small home system, it says there are 2595 executables on my PATH.
Many of these "commands" can be accessed from your favourite GUI front-end
(probably KDE or Gnome) by clicking on the right menu or button. They can all be
run from the command line. Programs that require GUI have to be run from a
terminal opened under a GUI.

Legend:<> = single special or function key on the keyboard.
For example <Ctrl> indicates the "control" key. italic = name
of the file or variable you probably want to substitute with your own.
fixed width = in-line Linux commands and filenames.

Notes for the UNIX Clueless:1. LINUX IS CASE-SENSITIVE. For
example: Netscape, NETSCAPE and nEtscape are three different commands. Also
my_filE, my_file, and my_FILE are three different files. Your user login name
and password are also case sensitive. (This goes with the tradition of UNIX and
the "c" programming language being case sensitive.) 2. Filenames can be up
to 256 characters long and can contain letters, numbers, "." (dot), "_"
(underscore), "-" (dash), plus some other not recommended characters. 3.
Files with names starting with "." are normally not shown by the ls
(list) or dir commands. Think of these files as "hidden". Use ls
-a (list with the option "all") to see these files. 4. "/" is an
equivalent to DOS "\" (root directory, meaning the parent of all other
directories). 5. Under Linux, all directories appear under a single
directory tree (there are no DOS-style drive letters). 6. In a configuration
file, a line starting with # is a comment.

7.1 Linux essential shortcuts and sanity
commands

<Ctrl><Alt><F1>Switch to the first
text terminal. Under Linux you can have several (6 in standard setup) terminals
opened at the same time.

<Ctrl><Alt><Fn> (n=1..6) Switch to the nth
text terminal.

ttyPrint the name of the terminal in which you are typing this
command.

<Ctrl><Alt><F7>Switch to the first GUI
terminal (if X-windows is running on this terminal).

<Ctrl><Alt><Fn> (n=7..12) Switch to the
nth GUI terminal (if a GUI terminal is running on screen n-1). On default,
nothing is running on terminals 8 to 12, but you can run another server
there.

<Tab>(In a text terminal) Autocomplete the
command if there is only one option, or else show all the available
options. THIS SHORTCUT IS GREAT! It even works at LILO prompt!

<ArrowUp>Scroll and edit the command history. Press
<Enter> to execute.

<Shift><PgUp>Scroll terminal output up. Work
also at the login prompt, so you can scroll through your bootup messages.

<Shift><PgDown>Scroll terminal output down.

<Ctrl><Alt><+>(in X-windows) Change to
the next X-server resolution (if you set up the X-server to more than one
resolution). For multiple resolutions on my standard SVGA card/monitor, I have
the following line in the file /etc/X11/XF86Config (the first
resolution starts on default, the largest determines the size of the "virtual
screen"): Modes "1024x768" "800x600" "640x480" "512x384" "480x300"
"400x300" "1152x864"

<Ctrl><Alt><BkSpc>(in X-windows) Kill the
current X-windows server. Use if the X-windows server crushes and cannot be
exited normally.

<Ctrl><Alt><Del>Shut down the system and
reboot. This is the normal shutdown command for a user at the text-mode console.
Don't just press the "reset" button for shutdown!

<Ctrl>cKill the current process (mostly in the text mode
for small applications).

<Ctrl>dLog out from the current terminal. See also
the next command.

<Ctrl>dSend [End-of-File] to the current process. Don't
press it twice else you also log out (see the previous command).

<Ctrl>sStop the transfer to the terminal.

<Ctrl>qResume the transfer to the terminal. Try if your
terminal mysteriously stops responding.

<Ctrl>zSend the current process to the background.

exitLogout. I can also use logout for the same
effect. (If you have started a second shell, e.g., using bash the
second shell will be exited and you will be back in the first shell, not logged
out.)

resetRestore a screwed-up terminal (a terminal showing funny
characters) to default setting. Use if you tried to "cat" a binary file. You may
not be able to see the command as you type it.

<MiddleMouseButton>Paste the text which is currently
highlighted somewhere else. This is the normal "copy-paste" operation in
Linux. (It doesn't work with Netscape and WordPerfect which use the MS
Windows-style "copy-paste". It does work in the text terminal if you enabled
"gpm" service using "setup".) Best used with a Linux-ready 3-button mouse
(Logitech or similar) or else set "3-mouse button emulation").

~(tilde) My home directory (normally the directory
/home/my_login_name). For example, the command cd
~/my_dir will change my working directory to the subdirectory
"my_dir" under my home directory. Typing just "cd" alone is an
equivalent of the command "cd ~".

.(dot) Current directory. For example, ./my_program
will attempt to execute the file "my_program" located in your current working
directory.

..(two dots) Directory parent to the current one. For example,
the command cd .. will change my current working directory one one
level up.

7.2 Common Linux commands--system
info

pwdPrint working directory, i.e., display the name of my
current directory on the screen.

hostnamePrint the name of the local host (the machine on which
you are working). Use netconf (as root) to change the name of the
machine.

whoamiPrint my login name.

id usernamePrint user id (uid) and his/her group id
(gid), effective id (if different than the real id) and the supplementary
groups.

datePrint or change the operating system date and time. E.g., I
could change the date and time to 2000-12-31 23:57 using this command:
date 123123572000To set the hardware (BIOS) clock from the
system (Linux) clock, use the command (as root) setclock

timeDetermine the amount of time that it takes for a process to
complete + other info. Don't confuse it with the date command. E.g. I
can find out how long it takes to display a directory content using:
time ls

whoDetermine the users logged on the machine.

rwho -a(=remote who) Determine all users logged on your
network. The rwho service must be enabled for this command to run. If it isn't,
run setup as root to enable "rwho".

finger user_nameSystem info about a user. Try:
finger root

lastShow listing of users last logged-in on your system.

history | moreShow the last (1000 or so) commands executed from
the command line on the current account. The "| more" causes the display to stop
after each screenful.

uptimeShow the amount of time since the last reboot.

ps(=print status) List the processes currently run by the
current user.

ps axu | moreList all the processes currently running, even
those without the controlling terminal, together with the name of the user that
owns each process.

topKeep listing the currently running processes, sorted by cpu
usage (top users first). In KDE, you can get GUI-based Ktop from "K"menu under
"System"-"Task Manager" (or by executing "ktop" in an X-terminal).

uname -a(= Unix name with option "all") Info on your (local)
server. I can also use guname (in X-window terminal) to display the
info more nicely.

cat /proc/cpuinfoCpu info--it show the content of the file
cpuinfo. Note that the files in the /proc directory are not
real files--they are hooks to look at information available to the kernel.

cat /proc/interruptsList the interrupts in use.

cat /proc/versionLinux version and other info

cat /proc/filesystemsShow the types of filesystems currently in
use.

cat /etc/printcapShow the setup of printers.

lsmod(As root. Use /sbin/lsmod to execute this command
when you are a non-root user.) Show the kernel modules currently loaded.

set|moreShow the current user environment.

echo $PATHShow the content of the environment variable "PATH".
This command can be used to show other environment variables as well. Use "set"
to see the full environment.

dmesg | lessPrint kernel messages (the content of the so-called
kernel ring buffer). Press "q" to quit "less". Use less
/var/log/dmesg to see what "dmesg" dumped into this file right after
the last system bootup.

7.3 Basic operations

any_command
--help |moreDisplay a brief help on a command (works with most
commands). "--help" works similar to DOS "/h" switch. The "more" pipe is needed
if the output is longer than one screen.

man topicDisplay the contents of the system manual pages
(help) on the topic. Try man man first. Press "q" to quit the viewer.
The command info topic works similar and may contain more
up-to-date information. Manual pages can be hard to read. Try
any_command --help for short, easy to digest help on a command.
If more info needed, have a look to the directory /usr/doc. To display
manual page from a specific section, I may use something like in this
example: man 3 exit (this displays an info on the command
exit from section 3 of the manual pages).

apropos topicGive me the list of the commands that have
something to to do with my topic.

help commandDisplay brief info on a bash (shell) build-in
command.

lsList the content of the current directory. Under Linux, the
command "dir" is an alias to ls. Many users have "ls" to be an alias to "ls
--color".

ls -al |moreList the content of the current directory, all
files (also those starting with a dot), and in a long form. Pipe the output
through the "more" command, so that the display pauses after each screenful.

cd directoryChange directory. Using "cd" without the
directory name will take you to your home directory. "cd -" will take you to
your previous directory and is a convenient way to toggle between two
directories. "cd .." will take you one directory up.

cp source destinationCopy files. E.g., cp
/home/stan/existing_file_name . will copy a file to my current
working directory. Use the "-r" option (for recursive) to copy the contents of
whole directories, e.g. , cp -r my_existing/dir/ ~ will copy a
subdirectory under my current working directory to my home directory.

mv source destinationMove or rename files. The same
command is used for moving and renaming files and directories.

ln source destinationCreate a hard link called
destination to the file called source. The link appears as a copy
of the original files, but in reality only one copy of the file is kept, just
two (or more) directory entries point to it. Any changes the file are
automatically visible throughout. When one directory entry is removed, the
other(s) stay(s) intact. The limitation of the hard links are: the files have to
be on the same filesystem, hard links to directories or special files are
impossible.

ln -s source destinationCreate a symbolic (soft) link
called "destination" to the file called "source". The symbolic link just
specifies a path where to look for the file. In contradistinction to hard links,
the source and destination don't not have to tbe on the same filesystem. In
comparison to hard links, the drawback of symbolic links are: if the original
file is removed, the link is "broken", symbolic links can also create circular
references (like circular references in spreadsheets or databases, e.g., "a"
points to "b" and "b" points back to "a").

rm filesRemove (delete) files. You must own the file in
order to be able to remove it. On many systems, you will be asked or
confirmation of deleation, if you don't want this, use the "-f" (=force) option,
e.g., rm -f * will remove all files in my current working
directory, no questions asked.

mkdir directoryMake a new directory.

rmdir directoryRemove an empty directory.

rm -r files(recursive remove) Remove files, directories,
and their subdirectories. Careful with this command as root--you can easily
remove all files on the system with such a command executed on the top of your
directory tree, and there is no undelete in Linux (yet). But if you really
wanted to do it (reconsider), here is how (as root): rm -rf /*

cat filename | moreView the content of a text file
called "filename", one page a time. The "|" is the "pipe" symbol (on many
American keyboards it shares the key with "\") The pipe makes the output stop
after each screenful. For long files, it is sometimes convenient to use the
commands head and tail that display just the beginning and the end of the file.
If you happened to use "cat" a binary file and your terminal displays funny
characters afterwards, you can restore it with the command "reset".

less filenameScroll through a content of a text file.
Press q when done. "Less" is roughly equivalent to "more" , the command you know
from DOS, although very often "less" is more convenient than "more".

pico filenameEdit a text file using the simple and
standard text editor called pico.

pico -w filenameEdit a text file, while disabling the
long line wrap. Handy for editing configuration files, e.g. /etc/fstab.

find / -name "filename"Find the file called "filename"
on your filesystem starting the search from the root directory "/". The
"filename" may contain wildcards (*,?).

locate filenameFind the file name of which contains the
string "filename". Easier and faster than the previous command but depends on a
database that normally rebuilds at night.

./program_nameRun an executable in the current
directory, which is not on your PATH.

touch filenameChange the date/time stamp of the file
filename to the current time. Create an empty file if the file
does not exist.

xinitStart a barebone X-windows server (without a windows
manager).

startxStart an X-windows server and the default windows
manager. Works like typing "win" under DOS with Win3.1

startx -- :1Start another X-windows session on the display 1
(the default is opened on display 0). You can have several GUI terminals running
concurrently. Switch between them using <Ctrl><Alt><F7>,
<Ctrl><Alt><F8>, etc.

xterm(in X terminal) Run a simple X-windows terminal.
Typing exit will close it. There are other, more advanced
"virtual" terminals for X-windows. I like the popular ones: konsole and
kvt (both come with kde) and gnome-terminal (comes with
gnome). If you need something really fancy-looking, try Eterm.

xboing(in X terminal). Very nice, old-fashioned game. Many
small games/programs are probably installed on your system. I also like
xboard (chess).

shutdown -h now(as root) Shut down the system to a halt. Mostly
used for a remote shutdown. Use <Ctrl><Alt><Del> for a
shutdown at the console (which can be done by any user).

haltreboot(as root, two commands) Halt or reboot
the machine. Used for remote shutdown, simpler to type than the previous
command.

Network apps

netscape(in X terminal) Run netscape
(requires a separate Netscape installation). The current versions of Netscape
(4.x) are known to be big and buggy. They occasionally crash by vanishing (no
other harm done). Also, when not connected to the network , Netscape likes to
refuse to do anything (looks like it hanged)-it revives when you connect.

netscape -display host:0.0(in X terminal) Run netscape
on the current machine and direct the output to machine named "host" display 0
screen 0. Your current machine must have a permission to display on the machine
"host" (typically given by executing the command xhost
current_machine_name in the xterminal of the machine host. Other
X-windows program can be run remotely the same way.

lynx file.htmlView an html file or browse the net from
the text mode.

pineA good text-mode mail reader. Another good and standard one
is elm. Your Netscape mail will read the mail from your Internet
account. pine will let you read the "local" mail, e.g. the mail your
son or a cron process sends to you from a computer on your home network. The
command mail could also be used for reading/composing mail, but it
would be inconvenient--it is meant to be used in scripts for automation.

elmA good tex-mode mail reader. See the previous command.

muttA really basic but extremally useful and fast mail reader.

mailA basic operating system tool for e-mail. Look at the
previous commands for a better e-mail reader. mail is good if you
wanted to send an e-mail from a shell script.

licq(in X term) An icq "instant messaging" client. Another good
one is kxicq. Older distributions don't have an icq client installed,
you have to do download one and install it.

talk username1Talk to another user currently logged on
your machine (or use "talk username1@machinename" to talk
to a user on a different computer) . To accept the invitation to the
conversation, type the command "talk username2". If somebody is
trying to talk to you and it disrupts your work, your may use the command
"mesg n" to refuse accepting messages. You may want to use
"who" or "rwho" to determine the users who are currently
logged-in.

telnet serverConnect to another machine using the TELNET
protocol. Use a remote machine name or IP address. You will be prompted for your
login name and password--you must have an account on the remote machine to
login. Telnet will connect you to another machine and let you operate on it as
if you were sitting at its keyboard (almost). Telnet is not very
secure--everything you type goes in open text, even your password!

rlogin server(=remote login) Connect to another machine.
The login name/password from your current session is used; if it fails you are
prompted for a password.

rsh server(=remote shell) Yet another way to connect to
a remote machine. The login name/password from your current session is used; if
it fails you are prompted for a password.

ftp serverFtp another machine. (There is also
ncftp which adds extra features and gftp for GUI .) Ftp is
good for copying files to/from a remote machine. Try user "anonymous" if you
don't have an account on the remote server. After connection, use "?" to see the
list of available ftp commands. The essential ftp command are: ls
(see the files on the remote system), ASCII, binary (set the
file transfer mode to either text or binary, important that you select the
proper one ), get (copy a file from the remote system to the local
system), mget (get many files at once), put (copy a file from
the local system to the remote system), mput (put many files at once),
bye (disconnect). For automation in a script, you may want to use
ncftpput and ncftpget, for example: ncftpput -u
my_user_name -p my_password -a remote.host.domain remote_dir *local.html

minicomMinicom program (looks like "Procomm for Linux").

File (de)compression

tar -zxvf filename.tar.gz(=tape archiver) Untar a tarred and compressed tarball (*.tar.gz or *.tgz)
that you downloaded from the Internet.

tar -xvf filename.tarUntar a tarred but uncompressed
tarball (*.tar).

gunzip filename.gzDecompress a zipped file (*.gz" or
*.z). Use gzip (also zip or compress) if you wanted to
compress files to this file format.

unzip filename.zipDecompress a file (*.zip) zipped with
a compression utility compatible with PKZIP for DOS.

unarj e filename.arjExtract the content of an *.arj
archive.

uudecode -o outputfilefilenameDecode a file
encoded with uuencode. uu-encoded files are typically used for
transfer of non-text files in e-mail (uuencode transforms any file into an ASCII
file).

7.4 Process control

ps(=print status) Display the list of
currently running processes with their process IDs (PID) numbers. Use ps
axu to see all processes currently running on your system (also those of
other users or without a controlling terminal), each with the name of the owner.
Use "top" to keep listing the processes currently running.

fg PIDBring a background or stopped process to the
foreground.

bg PIDSend the process to the background. Opposite to
fg. The same can be accomplished with <Ctrl>z. If you have stopped
jobs, you have to type exit twice in row to log out.

any_command&Run any command in the background (the
symbol "&" means "run the proceeding command in the background").

batch any_commandRun any command (usually one that is
going to take more time) when the system load is low. I can logout, and the
process will keep running.

at 17:00Execute a command at a specified time. You will
be prompted for the command(s) to run, until you press <Ctrl>d.

kill PIDForce a process shutdown. First determine the
PID of the process to kill using ps.

killall program_nameKill program(s) by name.

xkill(in an xwindow terminal) Kill a GUI-based program with
mouse. (Point with your mouse cursor at the window of the process you want to
kill and click.)

lpc(as root) Check and control the printer(s). Type "?" to see
the list of available commands.

lpqShow the content of the printer queue. Under KDE
(X-Windows), you may use GUI-based "Printer Queue" available from
"K"menu-Utilities.

lprm job_numberRemove a printing job "job_number" from
the queue.

nice program_nameRun program_name adjusting its
priority. Since the priority is not specified in this example, it will be
adjusted by 10 (the process will run slower), from the default value (usually
0). The lower the number (of "niceness" to other users on the system), the
higher the priority. The priority value may be in the range -20 to 19. Only root
may specify negative values. Use "top" to display the priorities of the running
processes.

renice -1 PID(as root) Change the priority of a running
process to -1. Normal users can only adjust processes they own, and only up from
the current value (make them run slower).

<Ctrl>c, <Ctrl>z, <Ctrl>s, and
<Ctrl>q also belong to this chapter but they were described previously.
In short they mean: stop the current command, send the current command to the
background, stop the data transfer, resume the data transfer.

linuxconfig(as root, either in text or graphical mode). You can
access and change hundreds of setting from it. Very powerful--don't change too
many things at the same time, and be careful with changing entries you don't
understand.

xvidtune(in X-terminal). Adjust the settings of the graphical
display for all resolutions so as to eliminate black bands, shift the display
right/left/up/down, etc. (First use the knobs on your monitor to fit your text
mode correctly on the screen.) To make the changes permanent, display the
frequencies on the screen and transfer them to the setup file
/etc/X11/XF86Config.

alias ls="ls --color=tty"Create an alias for the command "ls"
to enhance its format with color. In this example, the alias is also called "ls"
and the "color" option is only envoke when the output is done to a terminal (not
to files). Put the alias into the file /etc/bashrc if you would like
the alias to be always accessible to all users on the system. Type
"alias" alone to see the list of aliases on your system.

adduser user_nameCreate a new account (you must be
root). E.g., adduser barbara Don't forget to set up the
password for the new user in the next step. The user home directory is
/home/user_name.

useradd user_nameThe same as the command " adduser
user_name ".

userdel user_nameRemove an account (you must be a root).
The user's home directory and the undelivered mail must be dealt with separately
(manually because you have to decide what to do with the files).

groupadd group_nameCreate a new group on your system.
Non-essential but can be handy even on a home machine with a small number of
users.

passwdChange the password on your current account. If you are
root, you can change the password for any user using: passwd
user_name

chmod perm filename(=change mode) Change the file access
permission for the files you own (unless you are root in which case you can
change any file). You can make a file accessible in three modes: read (r), write
(w), execute (x) to three classes of users: owner (u), members of the same group
as the owner (g), others on the system (o). Check the current access permissions
using: ls -l filenameIf the file is accessible to all
users in all modes it will show: rwxrwxrwxThe first triplet
shows the file permission for the owner of the file, the second for his/her
group, the third for others. A "no" permission is shown as "-". E.g., this
command will add the permission to read the file "junk" to all
(=user+group+others): chmod a+r junkThis command will remove
the permission to execute the file junk from others: chmod o-x junkAlso try here for
more info. You can set the default file permissions for the news files that
you create using the command umask (see man umask).

chown new_ownername filenamechgrp new_groupname
filenameChange the file owner and group. You should use these two
commands after you copy a file for use by somebody else.

su(=substitute user id) Assume the superuser (=root) identity
(you will be prompted for the password). Type "exit" to return you to your
previous login. Don't habitually work on your machine as root. The root account
is for administration and the su command is to ease your access to the
administration account when you require it. You can also use "su" to assume any
other user identity, e.g. su barbara will make me "barbara" (password
required unless I am a superuser).

kernelcfg(as root in X terminal). GUI to to add/remove kernel
modules. You can do the same from the command line using the command
"insmod", but "insmode" is less "newbie-friendly".

lsmodList currently loaded kernel modules. A module is like a
device driver--it provides operating system kernel support for a particular
piece of hardware or feature.

modprobe -l |moreList all the modules available for your
kernel. The available modules are determined by how your Linux kernel was
compliled. Every possible module/feature can be compiled on linux as either
"hard wired" (fast, non-removable), "module" (maybe slower, but loaded/removable
on demand), or "no" (no support for this feature at all).

insmod parportinsmod ppa(as root) Insert modules
into the kernel (a module is roughly an equivalent of a DOS device driver). This
example shows how to insert the modules for support of the external parallel
port zip drive (it appears to be a problem to get the external zip drive to
work in any other way under RH6.0 ).

rmmod module_name(as root, not essential). Remove the
module module_name from the kernel.

setserial /dev/cua0 port 0x03f8 irq 4(as root) Set a serial
port to a non-standard setting. The example here shows the standard setting for
the first serial port (cua0 or ttyS0). The standard PC settings for the second
serial port (cua1or ttyS1) are: address of i/o port 0x02f8, irq 3. The third
serial port (cua2 or ttyS2): 0x03e8, irq 4. The forth serial port (cua3 or
ttyS3): 0x02e8, irq 3. Add your setting to /etc/rc.d/rc.local if you
want it to be set at the boot time. See man setserial for good a overview.

fdisk(as root) Linux hard drive partitioning utility (DOS has a
utility with the same name).

cd /usr/src/linux-2.0.36make xconfig(as root in X
terminal). Nice GUI front-end for configuration of the kernel options in
preparation for compilation of your customized kernel. (The directory name
contains the version of your Linux kernel so you may need to modify the
directory name if your Linux kernel version is different than 2.0.36 used in
this example. You also need the "Tk" interpreter and the kernel source code
installed. ) The alternatives to "make xconfig" are: "make config" (runs a
scripts that asks you questions in the text mode) and "make menuconfig" (runs a
text-based menu-driven configuration utility). Try: less
/usr/doc/HOWTO/Kernel-HOWTO for more information. After the
configuration, you may choose to proceed with kernel compilation of the
new kernel by issuing the following commands: make depmake
zImageThe last command will take some time to complete (maybe 0.5 h,
depending on your hardware). It produces the file "zImage", which is your new
Linux kernel. Next: make modulesmake modules_installRead: /usr/doc/HOWTO/Kernel-HOWTO for information on how to install the new
kernel. You will probably also find it useful to read "man depmode".
Configuration, compilation and installation of a new kernel is not difficult but
it CAN lead to problems if you don't know what you are doing. Compilation of
a kernel is a good way to test your hardware, because it involves a massive
amount of computing. If your hardware is "flaky", you will most likely receive
the "signal 11" error (read the beatiful
/usr/doc/FAQ/txt/GCC-SIG11-FAQ). See this for details
on kernel upgrade.

depmod -a(as root) Build the module dependency table for the
kernel. This can, for example, be useful after installing and booting a new
kernel. Use "modprobe -a" to load the modules.

ldconfig(as root) Re-create the bindings and the cache for the
loader of dynamic libraries ("ld"). You may want to run ldconfig after an
installation of new dynamically linked libraries on your system. (It is also
re-run every time you boot the computer, so if you reboot you don't have to run
it manually.)

mknod /dev/fd0 b 2 0(=make node, as root) Create a device file.
This example shows how to create a device file associated with your first floppy
drive and could be useful if you happened to accidentally erase it. The options
are: b=block mode device (c=character mode device, p=FIFO device, u=unbuffered
character mode device). The two integers specify the major and the minor device
number.

fdformat /dev/fd0H1440mkfs -c -t ext2(=floppy
disk format, two commands, as root) Perform a low-level formatting of a floppy
in the first floppy drive (/dev/fd0), high density (1440 kB). Then make a Linux
filesystem (-t ext2), checking/marking bad blocks (-c ). Making the files system
is an equivalent to the high-level format.

badblocks /dev/fd01440 1440(as root) Check a high-density
floppy for bad blocks and display the results on the screen. The parameter
"1440" specifies that 1440 blocks are to be checked. This command does not
modify the floppy.

dd if=/dev/fd0H1440 of=floppy_imagedd if=floppy_image
of=/dev/fd0H1440(two commands, dd="data duplicator") Create an image
of a floppy to the file called "floppy_image" in the current directory. Then
copy floppy_image (file) to another floppy disk. Works like DOS
"DISKCOPY".

Program installation

rpm -ivh filename.rpm(=RedhatPackageManager, install, verbose, hashes displayed to show progress,
as root.) Install a content of RedHat rpm package(s) and print info on what
happened. Keep reading if you prefer a GUI installation.

rpm -qf filename(=RedhatPackageManager, query, file.)
Find out the name of the *.rpm package to which the file filename (on
your hardrive) belongs.

rpm -e packagename(=RedhatPackageManager,
erase=uninstall.) Uninstall a package pagckagename. Packagname is
the same as the beginning of the *.rpm package file but without the dash and
version number.

kpackagegnorpmglint(in X terminal,
as root if you want to be able to install packages) GUI fronts to the Red Hat
Package Manager (rpm). "glint" comes with RH5.2, "gnorpm" with RH6.0, "kpackage"
comes with RH6.1 or must be installed separately but is the best of the three.
Use any of them to view which software packages are installed on your system and
the what not-yet-installed packages are available on your RedHat CD, display the
info about the packages, and install them if you want (installation must be done
as root).

Accessing drives/partitions

mountSee here for
details on mounting drives. Examples are shown in the next commands.

mount -t auto /dev/fd0 /mnt/floppy(as root) Mount the floppy.
The directory /mnt/floppy must exist, be empty and NOT be your current
directory.

mount -t auto /dev/cdrom /mnt/cdrom(as root) Mount the CD. You
may need to create/modify the /dev/cdrom file depending where your
CDROM is. The directory /mnt/cdrom must exist, be empty and NOT be your
current directory.

mount /mnt/floppy(as user or root) Mount a floppy as user. The
file /etc/fstab must be set up to do this. The directory
/mnt/floppy must not be your current directory.

mount /mnt/cdrom(as user or root) Mount a CD as user. The file
/etc/fstab must be set up to do this. The directory /mnt/cdrom
must not be your current directory.

umount /mnt/floppyUnmount the floppy. The directory
/mnt/floppy must not be your (or anybody else's) current working
directory. Depending on your setup, you might not be able to unmount a drive
that you didn't mount.

7.6 Network administration tools

netconf(as root) A very good menu-driven setup of your network.

pingmachine_nameCheck if you can contact another machine
(give the machine's name or IP), press <Ctrl>C when done (it keeps going).

route -nShow the kernel routing table.

nslookup host_to_findQuery your default domain name
server (DNS) for an Internet name (or IP number) host_to_find. This way
you can check if your DNS works. You can also find out the name of the host of
which you only know the IP number.

traceroute host_to_traceHave a look how you messages
trave to host_to_trace (which is either a host name or IP
number).

ipfwadm -F -p m(for RH5.2, seen next command for RH6.0) Set up
the firewall IP forwarding policy to masquerading. (Not very secure but simple.)
Purpose: all computers from your home network will appear to the outside world
as one very busy machine and, for example, you will be allowed to browse the
Internet from all computers at once.

echo 1 > /proc/sys/net/ipv4/ip_forwardipfwadm-wrapper -F
-p denyipfwadm-wrapper -F -a m -S xxx.xxx.xxx.0/24 -D
0.0.0.0/0(three commands, RH6.0). Does the same as the previous
command. Substitute the "x"s with digits of your class "C" IP
address that you assigned to your home network. See here for more
details. In RH6.1, masquarading seems broken to me--I think I will install
Mandrake Linux:).

ifconfig(as root) Display info on the network interfaces
currently active (ethernet, ppp, etc). Your first ethernet should show up
as eth0, second as eth1, etc, first ppp over modem as ppp0, second as ppp1, etc.
The "lo" is the "loopback only" interface which should be always active. Use the
options (see ifconfig --help) to configure the interfaces.

ifup interface_name(/sbin/ifup to it run as a
user) Startup a network interface. E.g.: ifup eth0ifup
ppp0Users can start up or shutdown the ppp interface only when the
right permission was checked during the ppp setup (using netconf ). To
start a ppp interface (dial-up connection), I normally use kppp available under
kde menu "internet".

ifdown interface_name(/sbin/ifdown to run it as
a user). Shut down the network interface. E.g.: ifdown ppp0 Also, see
the previous command.

knapster(in X terminal) Start the program to downolad mp3 files
that other users of napster have displayed for downloading. Really cool!

cdparanoia -B "1-"(CD ripper) Read the contents of
an audio CD and save it into wavefiles in the current directories, one track per
wavefile. The "1-" means "from track 1 to the last". -B forces putting
each track into a separate file.

gimp(in X terminal) A humble looking but very powerful image
processor. Takes some learning to use, but it is great for artists, there is
almost nothing you can't do with gimp. Use your mouse right button to get local
menus, and learn how to use layers. Save your file in the native gimp file
format *.xcf (to preserve layers) and only then flatten it and save as png (or
whatever). There is a large user manual /usr/

gphoto(in X terminal) Powerful photo editor.

giftopnm my_file.giff > my_file.pnmpnmtopng my_file.pnm > my_file.pngConvert the
propriatory giff graphics into a raw, portable pnm file. Then convert the pnm
into a png file, which is a newer and better standard for Internet
pictures (better technically plus there is no danger of being sued by the
owner of giff patents).